This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Friday, April 1, 2011

Congratulations, MESSENGER, on reaching Mercury!!

First image of Mercury ever taken from a
spacecraft in orbit around Mercury. Sent from Messenger,
which reached orbit around Mercury on March 17. Photo
sent on March 29, 2011
Photo credit: NASA
MESSENGER has successfully completed a complicated journey through the solar system to reach Mercury.  The path included one flyby of Earth (August 2005), two flybys of Venus (2006, 2007) and three flybys of Mercury (two in 2008, one in 2009).  It's returning the first new spacecraft data from Mercury since Mariner 10 sent data more than 30 years ago. MESSENGER was launched on August 3, 2004.

MESSENGER will be in a highly elliptical orbit around Mercury, coming as close as 200 km to the surface or being as far away as 15,000 km.

The rayed crater in this image is the impact crater Debussy. It is a central-peak crater with rays that extend hundreds of kilometers across the planet. This crater is visible in Earth-based radar images of mercury because of the prominent bright rays. The name honors the famous French composer, Claude Debussy (1862-1918).

Mercury, Venus, Earth and Mars are the rocky planets of our solar system.  Mercury is "extreme": the smallest, and the densest (after correcting for self-compression).  It has the oldest surface, and may have incipient, though not well-developed, plate tectonic features.  It has the most extreme variations in daily surface temperature.

MESSENGER scientists are focusing on six questions: (1) Why is Mercury so dense? (2) What is the geologic history? (3) What is the nature of its magnetic field? (4) What is the structure of its core? (5) What are the unusual materials at the poles (which are permanently shadowed)? (6) What volatiles are important at Mercury?

The MESSENGER website is here.

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